Study On Performance Of Ejector Based On Aerospike Nozzle

With the development of economy,cruise tourism has gradually become a fashionable leisure mode.The cruise ship needs to consume a lot of fresh water during the voyage,but carrying fresh water from the land cannot meet the huge water demand of the cruise ship.Therefore,it is an inevitable choice to improve the performance of desalination device to meet the fresh water demand of cruise ships.The performance of the ejector has an important influence on the thermal desalination system.Therefore,Aerospike nozzles have been designed in this paper,and the performance of Aeropike nozzles have been numerically simulated and experimentally studied under the condition of low temperature heat source.The specific research work of this paper is as follows:First of all,the geometric model of Aerospike nozzle ejector with linear profile had been established.The numerical simulation was carried out by Fluent under the conditions of generating temperature from 50? to 70? and evaporating temperature from 15? to 25?.The results showed that the maximum entrainment ratio of the ejector is 1.64 under the condition of generating temperature of 70? and evaporating temperature of 15?.Under the condition of generating temperature of 70? and evaporating temperature of 25?,the critical condensing pressure of the ejector is the highest,which is 5.39 kPa.The difference of internal fluid flow.characteristic between Aerospike nozzle and Laval nozzle were analyzed under the conditions of generating temperature of 65?,evaporating temperature of 15?and condensing temperature of 27.7?.Through the comparison,it was found that there were obvious differences in the internal flow field between the two kinds of ejectors.Through the comparative analysis of Aerospike nozzle ejectors with different plug cone sizes,it was found that the larger the plug cone size,the worse,the performance of the ejector,the smaller nozzle outlet pressure,the smaller Mach number and velosity at the axis,but the pressure at the axis is higher.Secondly,three kinds of curve surface Aerospike nozzles were designed according to the curve equations of conic curve,cubic curve and ellipse.The effects of profile curve,plug cone size and wall size on the performance of Aerospike ejector were investigatied.The results showed that the performance of the Aerospike nozzle with elliptic curve is the best,and the maximum value of the entrainment ratio is 1.81 under the condition of generating temperature of 50? and evaporating temperature of 25?.The critical condensing pressure of Aerospike nozzle ejector with cubic curve is higher.The maximum value of critical condensing pressure is 5.8 kPa under the condition of generating temperature of 70? and evaporating temperature of 25?.Moreover,it also can be seen from the results that the shape of the nozzle plug cone,the size of the nozzle plug cone and the size of the nozzle wall have a significant impact on the performance of the ejector and the fluid flow characteristic inside the ejector.Finally,the performance of the ejector with the Aerospike nozzles were carried out.The Aerospike nozzle with linear and the Aerospike nozzle with cubic curve were manufactured by 3D printing technology.The performance of the ejectors were investigated under generating temperature from 50? to 65? and evaporating temperature from 15? to 25?.The experimental results showed that COP(coefficient of performance)of Aerospike nozzle ejector with cubic curve is slightly higher than that of Aerospike nozzle ejector with linear,and the maximum value of COP is 1.58 under the condition of generating temperature of 50? and evaporating temperature of 25?.The critical condensing pressure of the ejector with cubic curve surface is significantly higher than the linear nozzle.The maximum value of the critical condensing pressure is 3.1 kPa,which appeared when the generating temperature is 65? and the evaporating temperature is 25?.